Radio frequency front-end circuit for wireless communication device

Abstract

A radio frequency (RF) front-end circuit includes a multiband antenna, an antenna switch, a duplexer, a communication mode selection switch, and a processor. The processor selectively connects the antenna switch or the duplexer to the multiband antenna using the communication mode selection switch. When the multiband antenna is connected to the antenna switch, the processor directs the antenna switch to transmit wireless signals used in a first wireless communication system received by or sent from the multiband antenna; when the multiband antenna is connected to the duplexer, the duplexer transmits wireless signals used in a second wireless communication system received by or sent from the multiband antenna.

What is claimed is: 
     
       1. A radio frequency (RF) front-end circuit, comprising:
 a multiband antenna; 
 an antenna switch including an antenna pin, a plurality of receiving pins, a plurality of transmitting pins, and a plurality of control pins; 
 a duplexer; 
 a communication mode selection switch connected to the multiband antenna, the antenna switch, and the duplexer, the communication mode selection switch including a control end; and 
 a processor connected to the control pins of the antenna switch and the control end of the communication mode selection switch respectively, wherein the processor controls the communication mode selection switch to selectively connect the antenna switch or the duplexer to the multiband antenna through the control end; when the multiband antenna is connected to the antenna switch, the processor controls the antenna switch to transmit wireless signals in a plurality of frequency bands used in a first wireless communication system through the control pins, wireless signals in one of the plurality of frequency bands received by one of the receiving pins, wireless signals in two of the plurality of frequency bands sent from the multiband antenna by one of the transmitting pins; and when the multiband antenna is connected to the duplexer, the duplexer transmits wireless signals used in a second wireless communication system received by or sent from the multiband antenna. 
 
     
     
       2. The RF front-end circuit as claimed in  claim 1 , wherein the wireless signals used in the first communication system are GSM signals in a plurality of GSM frequency bands, and the wireless signals used in the second communication system are UMTS signals in a predetermined UMTS frequency band. 
     
     
       3. The RF front-end circuit as claimed in  claim 2 , wherein the processor controls the antenna switch to transmit GSM signals received by or sent from the multiband antenna in a GSM frequency band selected from the plurality of GSM frequency bands when the multiband antenna is connected to the antenna switch, and the duplexer transmits UMTS signals received by or sent from the multiband antenna in the predetermined UMTS frequency band when the multiband antenna is connected to the duplexer. 
     
     
       4. The RF front-end circuit as claimed in  claim 3 , wherein the receiving pins for respectively receiving GSM signals in the plurality of GSM frequency bands received by the multiband antenna and the transmitting pins for transmitting to be sent GSM signals in the plurality of GSM frequency bands to the multiband antenna. 
     
     
       5. The RF front-end circuit as claimed in  claim 4 , further comprising a first filter connected to all the receiving pins for filtering the received GSM signals, and a first power amplifier connected to all the transmitting pins for amplifying the to be sent GSM signals. 
     
     
       6. The RF front-end circuit as claimed in  claim 4 , wherein the plurality of GSM frequency bands includes GSM850, GSM900, GSM1800, and GSM1900 frequency bands. 
     
     
       7. The RF front-end circuit as claimed in  claim 6 , wherein the antenna switch includes four receiving pins for respectively receiving GSM850, GSM900, GSM1800, and GSM1900 signals received by the multiband antenna, a transmitting pin for transmitting outgoing GSM850 and GSM900 signals to the multiband antenna, and a transmitting pin for transmitting to be sent GSM1800 and GSM1900 signals to the multiband antenna. 
     
     
       8. The RF front-end circuit as claimed in  claim 3 , further comprising a second filter connected to the duplexer for filtering the received UMTS signals, and a second power amplifier connected to the duplexer for amplifying the UMTS signals to be sent. 
     
     
       9. The RF front-end circuit as claimed in  claim 2 , wherein the predetermined UMTS frequency band is a UMTS 800 or UMTS 2100 frequency band.